The present invention relates to a door latch used for locking a hinged door, and especially relates to a door latch used as the interior equipment of an aircraft.
A hinged door is equipped for example to the opening area of a galley (cooking facility) or a toilet equipped as an interior member of an aircraft.
The locking mechanism of a hinged door applies a structure where a knob fixed to a sliding bolt is used to insert the bolt to a catch or to remove it therefrom. The bolt is slidably inserted to a bolt guide equipped to a housing, and the knob is formed to slide along a slit opened to the housing.
When a user holds the knob and slides it, the knob moves toward the end of the slit: formed to the housing, and stops when it collides to the end portion. Since the housing and the knob are formed of metal members to provide them necessary strength, the collision of the knob against the housing generates a large noise. Further, in order to prevent the bolt from moving around freely in the bolt guide and to maintain the bolt at a fully pulled-in position, a holding mechanism (detent) using a ball and a spring is equipped thereto. The detent structure also causes noise.
Since the interior members of the aircraft is positioned near the cabin, these noises reach the passengers on board, and causes problems such as awaking the passengers when they are sleeping.
Therefore, the present invention provides a door latch having a structure enabling to reduce the collision noise when opening/closing the door.
The door latch according to the present invention comprises a bolt guide mounted on a housing, a housing fixed to the door, a bolt inserted slidably to the bolt guide, a knob slidably guided by a slit formed to the housing, and a fastening means for connecting the knob and the bolt, wherein the area where the knob collides with the end portions of the slit formed to the housing is equipped with a plastic damper.
The door latch further comprises a hole with a bottom formed orthogonal to the axial line of the bolt at the rear end area of the bolt, a coil-spring inserted to the hole with a bottom, and a plastic ball biased by the coil-spring, wherein the bolt guide is equipped with a hole for receiving the ball.